Conventional robots are sometimes stiff and might not be suitable for moving through passages, such as passages that might have bends. Moreover, such robots might not be suitable for use in arteries in a living organism, such as a human body, in that such robots could possibly puncture artery walls.
More recently, fiber-reinforced elastomeric enclosure (FREE) actuators have been contemplated for possible use with or as a “soft” robot. FREEs are described in U.S. Application Publication No. 2015/0040753 (Bishop-Moser et al.), and entail one or more continuous fibers applied to a length of a hollow elastomeric cylinder in a helical pattern having a constant or uniform pitch. In the presence of a fluid medium, the FREE actuator experiences uniform change in shape. While the described FREE actuators appear promising for potential soft robot applications, the physical constraints presented by many soft robot usage environments may not be fully addressed.